US11633200B2 - Intravascular lithotripsy - Google Patents

Abstract

A medical device may include an elongated body, a balloon positioned at a distal portion of the elongated body, and one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon. The one or more pressure-wave emitters may be configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site. The at least one of the one or more pressure-wave emitters may include an electronic emitter comprising a first electrode and a second electrode. The first electrode and the second electrode may be arranged to define a spark gap between the first electrode and the second electrode, and the second electrode may comprise a portion of a hypotube.

Description

FIELD

The present disclosure relates to treatments for a calcified-plaque lesion in a patient's vasculature.

DESCRIPTION OF RELATED ART

During an intravascular lithotripsy (IVL) procedure, and more specifically, during an electrohydraulic lithotripsy (EHL) procedure, a clinician uses a catheter configured to emit high-energy pressure waves to break apart calcified-plaque lesions within a patient's vasculature.

SUMMARY

The present disclosure describes systems and techniques for producing and directing high-energy intravascular pressure waves for fragmentation and/or disintegration of calcified lesions within a vasculature of a patient. For purposes of illustration, the techniques herein are described primarily with respect to electrical-based systems and respective applications thereof, such as peripheral-vessel applications. However, it is to be understood that the techniques described herein may be assumed to be likewise applicable to similar systems based on other forms of energy, such as optical (e.g., laser) based systems and respective applications, such as coronary-treatment applications, except where explicitly noted below.

In general, the systems described herein include an energy generator removably coupled to a catheter having an array of pressure-wave emitters distributed within an interventional balloon. During a lesion-disintegration procedure, a clinician may advance the interventional balloon to a target treatment site within a patient's vasculature and inflate the balloon with an inflation fluid, such as a saline/contrast fluid mixture, until the balloon contacts at least a portion of the local vessel wall. The clinician may then actuate the energy generator, causing the catheter to generate a cavitation bubble within the fluid-filled balloon, propagating a high-energy pressure wave through the balloon and the calcified lesion. A secondary pressure wave can also result from the subsequent collapse of the fluid cavitation, further destabilizing the internal structure of the lesion.

In some examples, a medical device includes: an elongated body; a balloon positioned at a distal portion of the elongated body, the balloon configured to receive a fluid and thereby inflate such that an exterior surface of the balloon contacts an interior surface of a target treatment site within a vasculature of a patient; and one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon, the one or more pressure-wave emitters configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site, wherein at least one of the one or more pressure-wave emitters includes an electronic emitter including a first electrode and a second electrode, wherein the first electrode and the second electrode are arranged to define a spark gap between the first electrode and the second electrode, and wherein the second electrode includes a portion of a hypotube.

In some examples, the first electrode and the second electrode are embedded in an adhesive layer, and the electronic emitter further includes an elastomeric tube disposed radially between the elongated body and the second electrode. In some examples, the electronic emitter further includes a coil layer disposed radially between the elongated body and the elastomeric tube.

In some examples, the first electrode is oriented such that an exterior surface is non-parallel to the central longitudinal axis of the elongated body in the absence of external forces. In some examples, the first electrode is configured to move relative to the elongated body such that the exterior surface of the first electrode is oriented parallel to the central longitudinal axis during insertion and withdrawal of the medical device through the vasculature of the patient.

In some examples, the spark gap includes a first spark gap, the electronic emitter further includes a third electrode, and the third electrode is arranged so as to define a second spark gap between the second electrode and the third electrode. In some examples, the first electrode, the second electrode, and the third electrode are all portions of a common cylindrical surface of the hypotube. In some examples, the first electrode and the third electrode both define rounded triangular shapes, and the second electrode defines a parallelogram shape. In some examples, the first electrode, the second electrode, and the third electrode all define parallelogram shapes.

In some examples, the first electrode, the second electrode, and the third electrode all define rounded rectangular shapes. In some examples, the first electrode and the third electrode both define oval shapes, and the second electrode defines a semi-cylindrical shape. In some examples, the electronic emitter further includes a coupler layer positioned radially between the elongated body and the second electrode. In some examples, the coupler layer includes polyimide.

In some examples, the electronic emitter is wired such that the first electrode and the third electrode are independently actuatable. In some examples, the first electrode is ring-shaped; the second electrode is disc-shaped; and the first electrode is positioned around the second electrode.

In some examples, the electronic emitter further includes a third electrode and a fourth electrode; the third electrode is ring-shaped and the fourth electrode is disc-shaped; the third electrode is positioned around the fourth electrode; and the first, second, third, and fourth electrodes are all portions of a common cylindrical surface of the hypotube.

In some examples, the first electrode defines an inner radius of about 0.008 inches and an outer radius of about 0.0210 inches. In some examples, the hypotube defines a longitudinal length from about 0.080 inches to about 0.090 inches, and an outer circumference from about 0.10 inches to about 0.12 inches. In some examples, the hypotube defines an inner diameter of about 0.029 inches and an outer diameter of about 0.034 inches. In some examples, the first electrode is rectangular-prism shaped, and the first electrode extends at least partially radially inward through an outer surface of the elongated body.

In some examples, the first electrode extends radially inward through the elongated body and at least partially radially inward into an inner lumen of the elongated body. In some examples, the one or more pressure-wave emitters include five electronic emitters spaced longitudinally along the central longitudinal axis of the elongated body.

In some examples, an intravascular lithotripsy (IVL) system includes an energy generator; and a catheter, as referenced above.

In some examples, the energy generator is configured to control a treatment cycle by causing the electronic emitter to transmit a plurality of pressure-wave pulses, and the plurality of pressure-wave pulses includes about 80 pulses to about 300 pulses.

In some examples, a method of forming an electronic pressure-wave emitter of an intravascular lithotripsy (IVL) catheter includes: laser-cutting a hypotube to define at least a first electrode and a second electrode arranged to define a spark gap therebetween; inserting an elongated body through the laser-cut hypotube; flowing a potting material around the laser-cut hypotube; and removing obsolete support structures from the hypotube.

In some examples, the spark gap includes a first spark gap; and laser-cutting the hypotube further includes laser-cutting the hypotube to define a third electrode arranged so as to define a second spark gap between the second electrode and the third electrode.

In some examples, laser-cutting the hypotube includes laser-cutting the hypotube such that the first electrode and the third electrode both define rounded triangular shapes, and such that the second electrode defines a parallelogram shape. In some examples, laser-cutting the hypotube includes laser-cutting the hypotube such that the first electrode, the second electrode, and the third electrode all define parallelogram shapes.

In some examples, laser-cutting the hypotube includes laser-cutting the hypotube such that the first electrode, the second electrode, and the third electrode all define rounded rectangular shapes. In some examples, laser-cutting the hypotube includes laser-cutting the hypotube such that the first electrode and the third electrode both define oval shapes, and such that the second electrode defines a semi-cylindrical shape. In some examples, the method further includes wiring the first electrode and the third electrode so as to be independently actuatable.

In some examples, the spark gap includes a first spark gap; and laser-cutting the hypotube further includes laser-cutting the hypotube to define a third electrode and a fourth electrode arranged so as to define a second spark gap between the third electrode and the fourth electrode. In some examples, laser-cutting the hypotube further includes laser-cutting the hypotube such that: the first electrode and the third electrode are ring-shaped; the second electrode and the fourth electrode are disc-shaped; the first electrode is positioned around the second electrode; and the third electrode is positioned around the fourth electrode.

In some examples, a medical device includes an elongated body; a balloon positioned at a distal portion of the elongated body, the balloon configured to receive a fluid and thereby inflate such that an exterior surface of the balloon contacts an interior surface of a target treatment site within a vasculature of a patient; and one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon, the one or more pressure-wave emitters configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site, wherein at least one of the one or more pressure-wave emitters includes an electronic emitter including a first electrode, a second electrode, and a third electrode arranged to define a first spark gap between the first electrode and the second electrode, and a second spark gap between the second electrode and the third electrode, and wherein the first electrode, the second electrode, and the third electrode are portions of a common hypotube.

In some examples, the medical device includes a plurality of conductive wires configured to provide electrical energy to the emitter array, the plurality of conductive wires arranged according to a wiring configuration.

In some examples, the plurality of conductive wires extends generally parallel to the central longitudinal axis. In some examples, the wiring configuration includes a single-coil configuration such that the plurality of conductive wires coil helically around the elongated body, wherein adjacent coil turns of the plurality of conductive wires are spaced longitudinally along the central longitudinal axis. In some examples, the wiring configuration includes a double-coil configuration such that the plurality of conductive wires coil helically around the elongated body, wherein adjacent pairs of coil turns of the plurality of conductive wires are spaced longitudinally along the central longitudinal axis. In some examples, the wiring configuration includes a quadruple-coil configuration such that the plurality of conductive wires coil helically around the elongated body, wherein adjacent groups of four coil turns of the plurality of conductive wires are spaced longitudinally along the central longitudinal axis.

In some examples, the plurality of conductive wires includes a plurality of flat wires. In some examples, the plurality of conductive wires includes a plurality of round wires with flattened portions along the emitter array.

In some examples, the elongated body includes an inner body and an outer body; the outer body includes an inner layer and an outer layer; and the plurality of conductive wires coils around an exterior surface of the inner layer. In some examples, the outer layer of the outer body is flowed over the plurality of conductive wires such that the plurality of conductive wires is embedded in the outer layer. In some examples, the outer layer includes a potting layer or a heat-shrink tube. In some examples, the outer layer terminates proximally from the inner layer, such that a distal portion of the plurality of conductive wires is exposed to an interior of the balloon.

In some examples, the elongated body includes an inner body and an outer body, and the plurality of conductive wires coils around an exterior surface of the inner body such that the plurality of conductive wires forms a reinforcement layer for the elongated body.

In some examples, each of the plurality of emitters includes a respective voltage wire such that each of the plurality of emitters is independently actuatable. In some examples, the exterior surface of the balloon includes a polymer coating. In some examples, the exterior surface of the balloon includes a hydrophilic coating or a drug-based coating, such as an anti-thrombogenic coating or an anti-proliferative medication.

In some examples, the balloon includes two or more nested expandable substrates. In some examples, the two or more nested expandable substrates include at least an outer layer and an inner layer, wherein an interior surface of the outer layer is bonded to an exterior surface of the inner layer so as to form a single multi-layered extrusion. In some examples, the inner layer includes a high-pressure holding layer, and the outer layer includes a urethane layer.

In some examples, the balloon further includes a reinforcing structure. In some examples, the reinforcing structure includes a plurality of longitudinal fibers aligned parallel to the longitudinal axis of the balloon and a plurality of braided fibers. In some examples, the plurality of longitudinal fibers includes four to eight longitudinal fibers.

In some examples, the balloon includes an outer layer, an inner layer nested within the outer layer, and a cage structure nested between the outer layer and the inner layer, and the cage structure includes one or more longitudinal members oriented parallel to the longitudinal axis and one or more circumferential elements oriented perpendicular to the longitudinal axis.

In some examples, the medical device further includes a cage structure at least partially surrounding the exterior surface of the balloon. In some examples, the cage structure is rigidly coupled to the exterior surface of the balloon. In some examples, the cage structure includes a nitinol braid, metal wires, printed metals, radiopaque metal wires, or radiopaque printed metals. In some examples, the balloon includes a porous membrane configured to infuse a drug at the target treatment site.

In some examples, the balloon includes a plurality of longitudinal ribs configured to define folding guides as the balloon folds radially inward. In some examples, the plurality of longitudinal ribs includes an odd number of ribs. In some examples, the medical device includes a spring configured to longitudinally stretch the balloon in an absence of external forces.

In some examples, the medical device includes a fracturing member positioned on an external surface of the balloon. In some examples, the fracturing member includes a conductive wire running along the longitudinal axis of the balloon; and a plurality of piezo-elements positioned along the conductive wire, the plurality of piezo-elements configured to emit additional pressure waves against the calcified lesion. In some examples, the medical device includes a protective device positioned at the distal portion of the elongated body, and the protective device is configured to at least partially occlude the target treatment site and to collect fragmented lesion portions.

In some examples, the medical device includes a protective device positioned along the elongated body proximal to the balloon, and the protective device is configured to at least partially occlude the target treatment site and to collect fragmented lesion portions.

In some examples, the elongated body defines a lumen configured to receive a 0.0104″ to 0.035″ guidewire. In some examples, the medical device includes a handle positioned at a proximal end of the elongated body, wherein the handle includes an integral power supply for the emitter array. In some examples, the medical device includes a scoring member configured to contact and abrade the calcified lesion. In some examples, the scoring member defines a serrated exterior surface.

In some examples, the medical device includes means for controlling a primary direction of emission of the pressure waves. In some examples, the medical device includes a blocker unit positioned against an interior surface of the balloon and along only a portion of a circumference of the balloon, the blocker unit configured to absorb or reflect the pressure waves from the second portion of the circumference of the balloon. In some examples, the medical device includes a ceramic, porcelain, diamond, polyimide, or polyether ether ketone (PEEK).

In some examples, the medical device includes a radiopaque indicator positioned along the first portion of the circumference of the balloon, and the radiopaque indicator is configured to indicate an emitted direction of the pressure waves. In some examples, the radiopaque indicator includes a radiopaque wire positioned along the exterior surface of the balloon. In some examples, the radiopaque indicator includes a conductive wire of a fracturing element positioned along an exterior surface of the balloon, and the fracturing element further includes a plurality of piezoelectric elements configured to emit additional pressure waves through the calcified lesion.

In some examples, each of the one or more shockwave emitters defines a respective orientation, and the medical device further includes a user-input mechanism to modify the respective orientations of the one or more shockwave emitters. In some examples, each of the one or more shockwave emitters defines a respective fixed orientation, and the medical device further includes a user-input mechanism configured to independently actuate a first subset of the one or more shockwave emitters independently from a second subset of the one or more shockwave emitters. In some examples, the balloon includes two or more elongated sub-balloons oriented circumferentially around the central longitudinal axis, each sub-balloon including a respective subset of the one or more shockwave emitters.

In some examples, the system further includes a sensor configured to generate sensor data indicative of at least one parameter. In some such examples, the energy generator is configured to vary an amount of energy delivered based on the sensor data. In some examples, to vary the amount of energy, the energy generator is configured to vary a current level, a voltage level, a pulse duration, a pulse frequency, or a light intensity. In some examples, the sensor data includes fluid-pressure data, fluid-rate data, or temperature data. In some examples, the sensor includes an electrical-impedance monitor, an inflation-fluid flow-rate monitor, an inflation-fluid pressure monitor, a vessel-wall surface monitor, a vessel-diameter monitor, an interventional-balloon diameter monitor, or a plaque-fragmentation monitor. In some examples, the sensor includes a resonant-frequency sensor, and the energy monitor is configured to vary a pressure-wave frequency to approximate a resonant frequency of the calcified lesion. In some examples, the energy generator is configured to terminate an applied voltage based on the sensor data.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages are described below with reference to the drawings, which are intended to illustrate, but not to limit, the invention. In the drawings, like reference characters denote corresponding features consistently throughout similar examples.

FIG.1 is a conceptual diagram of an example intravascular lithotripsy (IVL) system, including an energy generator and a catheter having a pressure-wave-emitter array within an interventional balloon.

FIG.2 is a conceptual block diagram illustrating some example components of the energy generator ofFIG.1.

FIG.3 is a conceptual diagram illustrating some example components of the catheter ofFIG.1.

FIG.4A is a perspective view of a first example emitter assembly of the catheter ofFIG.1.

FIG.4B is a cross-sectional diagram of the emitter assembly ofFIG.4A.

FIG.5A is a perspective view of a second example emitter assembly of the catheter ofFIG.1.

FIG.5B is a cross-sectional diagram of the emitter assembly ofFIG.5A.

FIG.6A illustrates a third example emitter assembly of the catheter ofFIG.1.

FIG.6B is a cross-sectional diagram of the emitter assembly ofFIG.6A.

FIG.6C is a cross-sectional diagram of the emitter assembly ofFIG.6A with a potting-material layer removed to illustrate the components embedded therein.

FIG.7A is a 2-D representation of a first example design for a laser-cut hypotube of an emitter assembly, defining a non-orthogonal spark-gap orientation.

FIG.7B is a 3-D representation of the first example hypotube design ofFIG.7A.

FIG.8A is a 2-D representation of a second example design for a laser-cut hypotube of an emitter assembly, defining an orthogonal spark-gap orientation.

FIG.8B is a 2-D representation of a laser-cut hypotube array that includes the second example hypotube design ofFIG.8A.

FIG.9 is a 2-D representation of a third example design for a laser-cut hypotube of an emitter assembly, defining a circular spark-gap configuration.

FIG.10 is a flowchart illustrating an example technique for forming an emitter assembly for an IVL catheter.

FIGS.11A and11B illustrate an example flex circuit for an emitter assembly of an IVL catheter.

FIGS.12A and12B illustrate two example wiring configurations for the flex circuit ofFIGS.11A and11B.

FIGS.13A and13B illustrate two example wiring configurations for conductively wiring an electronic pressure-wave-emitter array.

FIGS.14A-14D are conceptual cross-sectional drawings illustrating four example wiring configurations for an electronic emitter array of the catheter ofFIG.1.

FIG.15A is a conceptual diagram illustrating an example wiring configuration for an electronic-emitter array having four emitter units.

FIG.15B is a conceptual diagram illustrating an example wiring configuration for an electronic-emitter array having five emitter units.

FIG.16A is a conceptual diagram illustrating a first example wiring configuration.

FIG.16B is a conceptual diagram illustrating a second example wiring configuration.

FIG.17A is a conceptual diagram illustrating an example IVL device having an optical-based emitter array.

FIG.17B is a cross-sectional view through the IVL device ofFIG.17A.

FIG.18 is a cross-sectional diagram of an example IVL device having a multiple-layered interventional balloon.

FIGS.19 and20 illustrate two example IVL devices having interventional balloons with protective structures.

FIG.21 illustrates an example IVL device having a pair of scoring members.

FIG.22 illustrates an example IVL device having a fracturing element.

FIG.23 illustrates an example IVL device having a spring mechanism.

FIG.24 illustrates an example IVL device having a distal protective member.

FIG.25 illustrates the IVL system ofFIG.1 with an example closed-loop energy-delivery feedback mechanism.

FIG.26 illustrates an example handle for the IVL catheter ofFIG.1.

FIG.27 is a cross-sectional view through a first example directionally focused IVL device.

FIG.28A is a perspective view, andFIG.28B is a cross-sectional view of a second example directionally focused IVL device.

FIG.29A is a perspective view, andFIG.29B is a cross-sectional view of a third example directionally focused IVL device.

DETAILED DESCRIPTION

Although specific examples are disclosed below, inventive subject matter extends beyond the specifically disclosed examples to other alternative examples and/or uses and to modifications and equivalents thereof. Thus, the scope of the claims appended hereto is not limited by any of the particular examples described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain examples; however, the order of description should not be construed to imply that these operations are order-dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components.

For purposes of comparing various examples, certain aspects and advantages of these examples are described. Not necessarily all such aspects or advantages are achieved by any particular example. Thus, for example, various examples may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

COMPONENT INDEX

• 100—Intravascular Lithotripsy (IVL) System
• 102—Energy Generator
• 104—Catheter
• 106—Elongated Catheter Body
• 108—IVL Device
• 110—Interventional Balloon
• 112—Pressure-Wave-Emitter Array
• 114A—First Emitter
• 114B—Second Emitter
• 114C—Third Emitter
• 114D—Fourth Emitter
• 114E—Fifth Emitter
• 116—Central Longitudinal Axis
• 118—Removable Cable
• 202—Power-Input Connector
• 204—Catheter Connector
• 208—Internal Power Supplies
• 210—High-Voltage DC-DC Converter
• 212—High-Voltage Capacitor and Transistor Switch
• 216—Voltage-and-Current Measurement Unit
• 218—Processor218
• 222—Device Identification Unit
• 224—Power Module
• 226—User-Interface (UI) Control Processor
• 234—User Interface
• 302—Proximal Catheter Portion
• 304—Distal Catheter Portion
• 306—Catheter Hub
• 308—Access Port
• 310—Inflation Port
• 312—Power Port
• 314—Strain Relief
• 316—Outer Elongated Structure
• 318—Inner Elongated Structure
• 320—Inflation Lumen
• 322—Guidewire Lumen
• 324—Distal Port
• 326—Exterior Balloon Coating
• 400—First Electric Emitter Assembly
• 402A—First Electrode
• 402B—Second Electrode
• 402C—Third Electrode
• 404A—First Spark Gap
• 404B—Second Spark Gap
• 406A—First Wire
• 406B—Second Wire
• 408—Inflation Fluid
• 410—Hypotube
• 412—Potting Material
• 414—Electrode Edges
• 416—Elastomeric Layer
• 418—Coils
• 420—Polymer Layer
• 500—Second Electric Emitter Assembly
• 502A—First Emitter Electrode
• 502B—Hypotube Electrode
• 502C—Second Emitter Electrode
• 504—Insulating Layer
• 506—Polyimide Inner Elongated Structure
• 508A,508B—Spark Gaps
• 600—Third Electric Emitter Assembly
• 602A—First Emitter Electrode
• 602B—Hypotube Electrode
• 602C—Second Emitter Electrode
• 608—Spark Gap
• 700—First Hypotube Design
• 800—Second Hypotube Design
• 802A—First Electrode
• 802B—Second Electrode
• 802C—Third Electrode
• 804A—First Spark Gap
• 804B—Second Spark Gap
• 806—Support Structures
• 810A—Circumferential Length
• 810B—Longitudinal Length
• 810C—Electrode Edge Length
• 810D—Spark Gap Width
• 810E—Support Structure Width
• 812—Hypotube-Array Design
• 814—Coupling Supports
• 816—Removable Supports
• 900—Third Hypotube Design
• 902A—First Ring Electrode
• 902B—First Disc Electrode
• 902C—Second Ring Electrode
• 902D—Second Disc Electrode
• 904—Spark Gaps
• 906—Support Structures
• 910A—Circumferential Length
• 910B—Longitudinal Length
• 910C—Support Structure Width
• 1000—Assembly Technique
• 1002-1010—Assembly Steps
• 1100—Flex Circuit
• 1102A—First Electrode
• 1102B—Second Electrode
• 1102C—Third Electrode
• 1104—Spark Gaps
• 1108—Flexible Substrate
• 1110A—Circumferential Length
• 1110B—Flex Circuit Longitudinal Length
• 1110C—Rectangle Longitudinal Length
• 1110D—Prong Circumferential Width
• 1110E—Prong Longitudinal Length
• 1110F—Prong Gap Circumferential Length
• 1112—Prongs
• 1200A—First Flex-Circuit Wiring Configuration
• 1200B—Second Flex-Circuit Wiring Configuration
• 1202—Top Wire
• 1204—Bottom Wire
• 1206—Top Wire
• 1208—Middle Wire
• 1210—Bottom Wire
• 1300A—First Wiring Configuration
• 1300B—Second Wiring Configuration
• 1302—Inner Elongated Structure
• 1304—Outer Elongated Structure
• 1306—Outer Structure Inner Layer
• 1308—Outer Structure Outer Layer
• 1310—Outer Structure Outer Layer Termination Point
• 1312—Outer Structure Inner Layer Termination Point
• 1400A-D—Wiring Configurations
• 1402—Wire Loop-Back Point
• 1404—Distal Balloon Cone
• 1406—Emitters
• 1408—Exposed Wire Conductor Points
• 1500A—First Wiring Configuration
• 1500B—Second Wiring Configuration
• 1502A—Four-Emitter Array
• 1502B—Five-Emitter Array
• 1504—Electric Emitters
• 1506—Ground Wire
• 1600A—First Wiring Configuration
• 1600B—Second Wiring Configuration
• 1602—Emitter Array
• 1604—Emitters
• 1606—Conductive Wires
• 1700—IVL Device
• 1702—Optical Emitters
• 1704—Optical Fibers
• 1800—IVL Device
• 1802—Balloon Outer Layer
• 1804—Balloon Inner Layer
• 1806—Balloon Middle Layer
• 1810—Interventional Balloon
• 1900—Interventional Device
• 1902—First Protective Structure
• 1904—Longitudinal Members
• 1906—Circumferential Members
• 2000—IVL Device
• 2002—Second Protective Structure
• 2100—IVL Device
• 2102—Scoring Members
• 2200—IVL Device
• 2202—Fracturing Element
• 2204—Wire
• 2206—Piezoelectric Elements
• 2300—IVL Device
• 2302—Spring
• 2304A—Spring Proximal End
• 2304B—Spring Distal End
• 2400—IVL Device
• 2402—Distal Protective Device
• 2404—Elongated Element
• 2406—Expandable Basket Member
• 2502—Sensor
• 2600—Catheter Handle
• 2602—Integrated Power Supply
• 2700—IVL Device
• 2702—Wave Director
• 2704—Visual Direction Indicator
• 2800—IVL Device
• 2814—Emitter Assemblies
• 2816—Emitter Units
• 2900—IVL Device
• 2902—Sub-Balloons

During an intravascular lithotripsy (IVL) procedure, and more specifically, during an electrohydraulic lithotripsy (EHL) procedure, a clinician uses high-energy pressure waves to break apart calcified-plaque lesions within a patient's vasculature. Typical IVL systems suffer from a number of disadvantages that limit the efficacy of the treatment. For instance, IVL catheters typically emit pressure waves that propagate around the entire inner circumference of the vessel wall at a target treatment site. In instances in which the calcified lesion is limited to only a portion of the vessel-wall circumference, for example, eccentric, focal, and/or nodular-shaped lesions, pressure waves that propagate in all directions can present less-effective disintegration or a waste of applied energy. As a second example, in addition to directional limitations, typical IVL catheters are designed to deliver a fixed level of energy and/or power, regardless of the particular clinical need (e.g., lesion size and/or density) at the target treatment site, presenting a similar set of difficulties and/or effectiveness limitations.

As a third example, many IVL-catheter designs include a distal interventional balloon for distributing the pressure waves across the surrounding tissue. In some cases, these interventional balloons may rupture in response to an above-threshold wave pressure or when treating heavily calcified lesions. If the balloon tears around its entire circumference, the distal portion of the balloon may “bunch up” around the distal catheter tip, causing a more difficult and/or more complex withdrawal from the patient, e.g., by removing an outer sheath or other introducer in order to remove the balloon catheter. As a final example, certain features of typical interventional balloons can increase resistance against inserting the catheter into the introducer sheath at the beginning of the procedure, and/or withdrawing the catheter through the introducer sheath at the end of the procedure. For instance, bulky balloon “cones” and ineffective re-wrapping of balloon “pleats” can require the clinician to apply additional undue force to successfully perform the IVL procedure.

The present disclosure describes systems and techniques for producing and directing high-energy intravascular pressure waves for fragmentation and/or disintegration of calcified lesions within a vasculature of a patient. For illustration purposes, the techniques herein are described primarily with respect to electrical-based systems and respective applications thereof, such as peripheral-vessel applications. However, it is to be understood that the techniques described herein may be assumed to be likewise applicable to similar systems based on other forms of energy, such as optical (e.g., laser) based systems and respective applications, such as coronary-treatment applications, except where explicitly noted below.

In general, the systems described herein include an energy source and an IVL catheter having a distal IVL device, including an interventional balloon and a pressure-wave-emitter array. During a lesion-disintegration procedure, a clinician may advance the interventional balloon to a target treatment site within a patient's vasculature and inflate the balloon with an inflation fluid, such as a saline/contrast-fluid mixture, until the balloon contacts at least a portion of the local vessel wall. The clinician may then actuate the energy generator, causing the catheter to generate a cavitation bubble within the fluid-filled balloon, propagating a high-energy pressure wave through the balloon and the calcified lesion. A secondary pressure wave can also result from the subsequent collapse of the fluid cavitation, further destabilizing the internal structure of the lesion.FIG.1 is a conceptual diagram illustrating anexample IVL system100. As shown inFIG.1,IVL system100 includes at least anenergy generator102 and anIVL catheter104 removably coupled toenergy generator102, such as via a catheter-connector interface204. In some examples, aremovable cable118 may be connected betweengenerator102 andcatheter104 to provide energy tocatheter104. As detailed further below, an energy source (e.g., a battery, capacitor, etc.) may additionally or alternatively be integrated intocatheter104.Catheter102 includes anelongated body106 and anIVL device108 positioned at a distal portion ofelongated body106.Elongated body106 is configured to navigate a tortuous vasculature of a patient toward a target treatment site, e.g., a calcified-plaque lesion within a vessel.

As shown inFIG.1,IVL device108 includes a fluid-inflatableinterventional balloon110 and a pressure-wave-emitter array112 positioned withinballoon110. Emitter array112 includes one or moreindividual emitter units114A-114E. For instance,interventional balloon110, or a distal portion ofelongated body106 passing therethrough, may define a centrallongitudinal axis116, andemitter units114A-114E may be distributed longitudinally along centrallongitudinal axis116. It is to be noted thatindividual emitter units114A-114E are also referred to throughout this disclosure as “emitters” (e.g., in reference to an emitter unit as a whole), as well as “emitter assemblies” (e.g., in reference to a particular arrangement of sub-components collectively forming the emitter unit).

In particular, the example emitter array112 shown inFIG.1 includes afirst emitter unit114A, asecond emitter unit114B, athird emitter unit114C, afourth emitter unit114D, and afifth emitter unit114E. While fiveemitter units114 are illustrated inFIG.1, emitter array112 ofIVL device108 may include as few as one individual emitter unit and up to as many emitter units as could reasonably fit withinballoon110. Eachemitter unit114 is configured to receive energy fromenergy generator102 and use the received energy to generate and transmit high-energy pressure waves throughballoon110 and across the target treatment site. As detailed further below,energy generator102 may generate and transmit energy in the form of electrical energy, optical energy, or a combination thereof. For instance,emitter units114 may use the received energy to generate a cavitation within the fluid insideballoon110, propagating one or more high-energy pressure waves radially outward throughballoon110 and the calcified lesion. In some cases, but not all cases, a secondary set of high-energy pressure waves can subsequently result from the collapse of the fluid cavitation, further destabilizing the internal structure of the calcified-plaque lesion. In some examples, one or more ofemitters114 can include an electrical-based emitter configured to receive electrical energy fromgenerator102, such as via one or more conductive wires, and generate a spark between a pair of electrodes, thereby triggering the initial cavitation. Additionally, or alternatively, one or more ofemitters114 can include an optical-based emitter configured to receive a high-energy optical (e.g., light) signal fromgenerator102, such as via one or more fiber-optic wires or tubes and direct the optical signal to trigger the initial cavitation.

FIG.2 is a block diagram illustrating some example components ofenergy generator102 ofFIG.1. A power input202 (e.g., for conductively coupling to a wall port or another electricity source) connects topower module224 and aninternal power supply208. As shown inFIG.2,power module224 can include, as various, non-limiting examples, a high-voltage DC-DC converter210, a high-voltage capacitor andtransistor switch212, a voltage and/orcurrent measurement unit216, and adevice identification unit222, configured to determine whethercatheter104 is an authorized device whilecatheter104 is connected viacatheter connector204. For instance,energy generator102 may be configured to disable energy output tocatheter connector204 when an unidentified device is connected.

Generator102 can include a memory and one or more processors, such asprocessor218 and/or user-interface-control processor226.UI control processor226 is configured to provide functionality for the user interface234 ofenergy generator102, such as a display screen, touch screen, buttons, or other manual controls enabling a user (e.g., a clinician) to operate theenergy generator102.

Although not illustrated inFIG.2, additionally or alternatively to electrical-energy-based components, in some examples,energy generator102 includes an optical signal unit configured to convert electrical power (e.g., from power input202) into a beam of light, such as a laser beam. The optical signal unit may then direct the optical signal into a carrying cable, such as an optical fiber, either coupled to catheter104 (FIG.1) or integrated as part ofcatheter104.

FIG.3 is a conceptual diagram showing some example components ofcatheter104 ofFIG.1. As shown inFIG.3,catheter104 includes aproximal portion302 and adistal portion304 opposite the proximal portion. Theproximal portion302 may include acatheter hub306 and/or a handle (as detailed further below).Catheter hub306 defines anaccess port308, aninflation port310, and apower port312.Access port308 enables the clinician to manipulate (e.g., maneuver, actuate, etc.) thedistal portion304, includingIVL device108. The clinician may useinflation port310 to inject an inflation fluid, such as a saline/contrast-fluid solution to inflateinterventional balloon110 to an expanded or inflated state, in which an exterior surface ofballoon110 contacts an interior surface of the vessel wall at the target treatment site.Power port312 is configured to interconnect with a power cable (not shown) to conductivelycouple catheter104 to energy generator102 (FIGS.1 and2).Catheter hub306 may also include astrain relief portion314 to reinforceelongated body106 and reduce kinking.

As shown inFIG.3, in some examples, but not all examples,elongated body106 may include an outerelongated structure316 and an innerelongated structure318. For instance, outerelongated structure316 may include a sheath or outer catheter defining aninflation lumen320. In some examples, outerelongated structure316 forms a proximal extension ofinterventional balloon110, such thatinflation lumen320 fluidically couplesinflation port310 to the interior cavity ofinterventional balloon110.

Innerelongated structure318 may include an inner catheter or other inner structure, positioned withininflation lumen320, configured to retainemitters114 of emitter array112. In some such examples, innerelongated structure318 may itself define aninner lumen322, e.g., configured to receive a guidewire viadistal port324. In other examples, such as depicted in subsequent figures,elongated body106 includes just a single layer defining a single inner lumen.

As described above,catheter104 is configured to advance through a patient's vasculature (e.g., through an arteriotomy) to position theballoon110 adjacent to a calcium lesion located at a target treatment site.IVL device108 may be configured to cause a first pressure-wave (or group of waves) by expanding a volume of liquid resulting from a phase change from a liquid into a liquid-vapor, which may cause a bubble to rapidly expand. A second pressure wave may occur as the bubble subsequently collapses. In some examples, theballoon110 has anexterior coating326, e.g., made from a polymer and/or other materials, as detailed further below. For instance,exterior coating326 may include a hydrophilic coating to improve navigability through the patient's vasculature. Additionally, or alternatively,exterior coating326 may include a drug coating, such as an anti-thrombogenic drug or an anti-proliferative medication, as well as an excipient to aid in drug transfer. As detailed further below,balloon110 may be or be porous/semi-permeable (e.g., a “weeping” balloon) for the infusion of drugs into the vessel, as compared to being injected into the vessel through a lumen.

FIG.4A is a perspective view of a first example emitter assembly400 (e.g.,emitter assembly114A ofFIG.1) ofcatheter104 ofFIG.1, andFIG.4B is a cross-sectional diagram ofemitter400 ofFIG.4A. In particular,FIGS.4A and4B illustrate anelectronic emitter400, including a pair ofconductive electrodes402A,402B defining afirst spark gap404A therebetween. In such examples,electrodes402A,402B are configured to receive electrical energy (e.g., an electric current) from energy generator102 (FIGS.1 and2) viaconductive wires406A,406B. The resulting spark across spark gap404 is configured to cavitate the surroundinginflation fluid408 to propagate high-energy pressure waves throughinflation fluid408.

In accordance with techniques of this disclosure, one or bothelectrodes402A,402B are subsections or portions of a cylindrical surface of acommon hypotube410. As used herein, a “hypotube” refers to a metallic tube with micro-engineered features along its length.

That is, particular sections of acylindrical hypotube410 may be removed (e.g., laser-cut) so as to form one or bothelectrodes402A,402B, and thespark gap404A therebetween. In some such examples, apotting material412, such as an adhesive layer, may be flowed overtop of the remaining portions of the cylindrical hypotube (e.g.,electrodes402A,402B) and then either hardened, or allowed to harden, to retain the hypotube portions in place. Some examples ofpotting materials412 include a polyurethane base, an acrylic base, a silicone base, or any other suitable material with sufficient dielectric strength. In some examples, but not all examples,excess potting material412 may be subsequently removed (e.g., scored, ablated, or milled-out) from betweenelectrodes402A,402B to re-establishspark gap404A, as necessary.

As illustrated further inFIG.4B, hypotube410 ofemitter assembly400 includes two pairs of conductive electrodes and respective spark gaps therebetween—first pair ofelectrodes402A,402B (withspark gap404A therebetween), and second pair ofelectrodes402B,402C (withspark gap404B therebetween). That is,electrode402B may be used as a common electrode for both ofelectrodes402A,402C, aligned relative to opposite edges ofelectrode402B. Put explicitly,first edge414A offirst electrode402A is aligned relative tosecond edge414B ofsecond electrode402B to definefirst spark gap404A. Additionally,third edge414C ofsecond electrode402B is aligned relative tofourth edge414D ofthird electrode402C to definesecond spark gap404B. In some examples, the two pairs of conductive electrodes may be wired to be simultaneously actuatable, or in other examples, may be wired to be separately actuatable, as detailed further below. Such wiring configurations enable the clinician to choose which emitter assemblies, or even particular electrode pairs, to activate for treatment of the calcified-plaque lesion. While a two-electrode-pair system is primarily shown and described herein, it should be noted that greater numbers of electrode pairs may also be incorporated intoemitter assembly400.

In some examples, hypotube410 may similarly define a three-electrode system, but rather than defining two emitter-electrode pairs, the three electrodes may consist of a working electrode, a counter electrode, and a reference electrode. For instance, while the working electrode and the counter electrode are configured to create the pressure-wave, the reference electrode's role is to act as a reference in measuring and controlling the working-electrode potential without passing any current itself.

As further illustrated inFIG.4B,electronic emitter assembly400 includes a plurality of nested layers (e.g., to defineelongated body106 therein). For instance, withinhypotube410 andpotting material412,emitter assembly400 includes anelastomeric layer416, such as a thermoplastic elastomer. One such example includes polyether block amide (e.g., PEBAX® from Arkema S.A. of Colombes, France). In some examples, but not all examples, withinelastomeric layer416,emitter assembly400 may includecoils418 of a spring layer associated with interventional balloon110 (FIG.1), as detailed further below. Finally, the most internal layer ofemitter assembly400 is asecondary polymer layer420, such as polyimide.Polymer layer420 may be tubular-shaped, defining a portion ofguidewire lumen322 therein.

According to some examples,emitter assembly400 is configured to implement a relatively high, redundant voltage. Accordingly, composing materials should be selected for low degradation, such that theIVL device108 lasts the duration of the IVL treatment. In some examples,catheter104 is configured to be single-use-only, whileenergy generator102 is considered to be theoretically infinitely reusable. In some examples, the number of pressure-wave “cycles” of an IVL treatment may range from about 80 wave pulses to about 300 wave pulses, but treatments may include more or fewer wave pulses, depending on the unique clinical parameters presented.

In some examples, the electrode pairs402A/402B and402B/402C may be made of narrow copper strips that are fixated on innerelongated structure318 inside of interventional balloon110 (FIGS.1,3). In some examples, but not all examples, eachelectrode402 may be cut, bent, or otherwise formed to define an angle relative to centrallongitudinal axis116. That is,electrodes402 may be configured to “tilt” away from centrallongitudinal axis116 in the absence of outside forces. During delivery through the patient's vasculature, a radially inward compressive force from the deflatedballoon110 may cause the electrodes to “flatten” toward the centrallongitudinal axis116.

FIG.5A is a perspective view of a second exampleelectronic emitter assembly500 of thecatheter104 ofFIG.1, andFIG.5B is a cross-sectional diagram of theemitter assembly500 ofFIG.5A. Specifically, theexample emitter assembly500 ofFIGS.5A and5B includes two laser-cut “emitter”electrodes502A,502C welded to a laser-cut polyimide “coupler”layer504. In this example,emitter electrodes502A,502C are shown to be generally oval-shaped, but other geometric shapes are contemplated.

A laser-cut “hypotube”electrode502B is also attached to thecoupler layer504 in betweenemitter electrodes502A,502C, so as to definerespective spark gaps508A,508B. In this example, hypotube-electrode502B is shown to be generally semi-cylindrical-shaped, but other geometric shapes are contemplated. A series offlat wires406A-406D may be utilized to deliver energy from the energy generator102 (FIGS.1 and2) to theemitter electrodes502A and502C; from theemitter electrodes502A,502C to additional emitter units114 (FIG.1) within theIVL device108; and from theadditional emitter units114 back to ground voltage.

As shown inFIGS.5A and5B, in this example, a polyimide innerelongated structure506 extends distally through the core of theemitter assembly500, as seen on the outside of the assembly inFIG.5A, or at the innermost circle inFIG.5B. The portion of the outermost concentric ring above centrallongitudinal axis116 is a laser-cut-hypotube electrode502B that passes energy to the opposing-side mirrored “emitter”electrodes502A,502C. The portion of the outermost concentric ring below centrallongitudinal axis116 is anotheremitter electrode502C welded to thewire406D. The rectangular extensions about thelongitudinal axis116 that carry on away from the emitter assembly on both sides are additionalflat wires406 that lead to and away from the emitters to carry energy for producing the pressure waves and then leading the voltage back to ground. The outer portion of theemitter assembly500 as seen inFIG.5A, or the middle core as seen inFIG.5B, is thefirst spark gap508A at which the current from theemitter electrode502A “jumps” to thehypotube electrode502B.

In some examples, but not all examples, a reflective surface or coating may be applied to the surface within the spark gaps508, in order to reflect the emitted pressure waves radially outward toward the interventional balloon110 (FIG.1). The reflective surface or coating may be, for instance, an acoustically opaque and non-conductive (e.g., insulative) material, such as a ceramic, porcelain, diamond, polyimide, polyether ether ketone (PEEK), another similar material, or any suitable combination thereof.

The penultimate core that lies just beneath both the laser-cut hypotube502B and theemitter electrode502A inFIG.5A, and which can be seen wrapped around the middle core inFIG.5B, is a coupler or insulatingmaterial504 that creates space between the inner lumen and theemitter electrode502A.

FIG.6A illustrates a third exampleelectronic emitter assembly600 ofcatheter104 ofFIG.1,FIG.6B is a cross-sectional diagram ofemitter assembly600, andFIG.6C is a cross-sectional diagram ofemitter assembly600 withpotting material412 removed to illustrate the components embedded therein. In particular,emitter assembly600 includes two laser-cut “emitter”electrodes602A,602C positioned opposite ahypotube electrode602B. As shown inFIG.6C, in some examples, but not all examples,emitter electrodes602A,602C are configured to breach the exterior surface of innerelongated structure506, e.g., to help retain theemitter electrodes602A,602B in place. In some such examples,emitter electrodes602A,602B extend radially inward through the entire wall of innerelongated structure506 and extend partially radially inward intoguidewire lumen322.Emitter electrodes602A,602B may additionally be potted in place, e.g., embedded withinpotting material412.

The thirdexample emitter assembly600 shown inFIGS.6A,6B, and6C shares similarities with the secondexample emitter assembly500 shown inFIGS.5A and5B, except for the differences noted herein. For instance, in both examples, a polyimide innerelongated structure506 extends distally through the core of the emitter assembly, as seen on the outside of theassembly600 inFIG.6A, or at the radially innermost circle inFIGS.6B and6C.

The portion of the outermost concentric ring above centrallongitudinal axis116 is a laser-cut hypotube electrode602B that passes energy to the opposing-side emitter electrodes602A,602C. As described above, below the centrallongitudinal axis116 inFIG.6C are twoemitter electrodes602A,602C that extend radially inward through both the outer surface and the inner surface ofelongated structure506. As shown particularly inFIG.6C, a plurality offlat wires406 are distributed circumferentially aroundlongitudinal axis116 that lead toward and away from theemitter electrodes602A,602C to carry energy for producing the high-energy pressure waves, and then leading proximally back to ground voltage. InFIG.6B, theseflat wires406 are represented as dashed lines embedded withinpotting material412, and as solid components inFIG.6C, as thepotting material412 has been removed to facilitate visualization of theflat wires406 in this space.

In the example ofFIGS.6A and6B, the spark gap608A (e.g., the site at which the electric current from theemitter electrode602A “jumps” to the hypotube electrode602B, is shown to be substantially filled withpotting material412. In other examples, the section ofpotting material412 within spark gap608A may be milled out or otherwise removed. Thepotting material412, shown just beneath both the laser-cut hypotube602B and theemitter602A inFIG.6A, and wrapped around innerelongated structure506, can include any suitable adhesive or potting material, such as an ultraviolet adhesive, an epoxy, or a reflowing polymer.

In some examples, a pressure-reflective material may be appended within and/or around spark gap608A, the reflective material configured to redirect the radially inward pressure waves to travel radially outward toward interventional balloon110 (FIGS.1,3).

FIGS.7A-9 illustrate three example electrode-design configurations for a laser-cut hypotube410 (FIG.4B) defining two or more conductive electrodes for an electronic emitter assembly400 (FIG.4). These hypotube designs may be cut (e.g., laser-cut) from a common 2-D surface. In some examples, the electrode designs may be cut from a planar 2-D surface, which may subsequently be formed into a cylindrical hypotube. In other examples, the electrode designs may be cut directly from a cylindrical hypotube.

Example materials that may be used to cut the conductive electrodes from the common planar surface or cylindrical hypotube include 304 SST, titanium, cobalt chromium, 316SST, or a nickel-titanium alloy (e.g., Nitinol), though other options are suitable, as long as they have low degradation, low resistivity, ductility, and are machinable through use of a laser. Additionally, the electrodes may be cut directly out of stents, so a flat sheet of material is not strictly necessary. In some examples, allemitters114 of emitter array112 (FIG.1) may be cut from a single continuous hypotube. This has the advantage of removing the need to weldindividual emitters114 to wires, thus facilitating the manufacturing process.

FIG.7A is a 2-D representation of a first example design for a laser-cut hypotube700 of an electronic emitter assembly400 (FIG.4), andFIG.7B is a 3-D representation of thefirst example hypotube400 ofFIG.7A. For instance,FIG.7B illustrates what hypotube400 ofFIG.7A would look like when rolled into its final tubular form. As one non-limiting, illustrative example, in the tubular form shown inFIG.7B,cylindrical hypotube700 may define an inner diameter of about 0.025 to about 0.035 (e.g., about 0.03 inches), and an outer diameter of about 0.03 inches to about 0.04 inches (e.g., about 0.035 inches).

Thehypotube design700 shown inFIGS.7A and7B largely corresponds to thehypotube design410 shown inFIG.4. For instance, hypotube700 definesfirst electrode pair402A/402B withspark gap404A therebetween, andsecond electrode pair402B/402C withspark gap404B therebetween.FIGS.7A and7B. illustrate a generally non-orthogonal hypotube design, in whichelectrodes402 are irregularly shaped, such thatspark gaps404A,404B are not oriented parallel to centrallongitudinal axis116. In particular, as shown inFIG.7A,electrodes402A and402C are generally shaped as rounded triangles (e.g., three-sided shapes with rounded corners), andelectrode402B is generally shaped as a parallelogram. However, other configurations are contemplated, such as all threeelectrodes402A-402C being shaped as parallelograms.

The relative angle betweenspark gaps404A,404B and centrallongitudinal axis116 may be varied across different emitters114 (FIG.1) to provide differing directions of propagation of the emitted pressure waves. In some such examples, the clinician may independently actuate different emitters to control this aspect of the IVL treatment.

FIG.8A is a 2-D representation of asecond example design800 for a laser-cut hypotube of an electronic emitter assembly400 (FIG.4). As compared to thehypotube410 shown inFIGS.7A and7B,hypotube design800 includes a more-orthogonal design, in whichspark gaps804A,804B are oriented parallel to centrallongitudinal axis116. For instance,electrodes802A-802C are more-regularly shaped, such as substantially rectangular, such thatspark gaps804A,804B are substantially parallel tolongitudinal axis116.

For purposes of illustration, some non-limiting examples of various dimensions ofhypotube800 are shown inFIG.8. For instance, hypotube800 (while in the flat configuration shown inFIG.8) may define a rectangle having acircumferential length810A of about 0.1 inch. Therectangular width810B (e.g., the longitudinal length ofhypotube800 along longitudinal axis116) can range from about 0.080 inches to about 0.090 inches.

Each ofelectrodes802A,802B,802C may include emitting edges414 (FIG.4), e.g., definingspark gaps804A,804B therebetween, havinglengths810C of about 0.040 inches to about 0.055 inches. The resulting spark gaps, then, may define gap widths from about 0.0025 inches to about 0.0040 inches.Hypotube800A may further include a plurality ofsupport structures806 configured to at least temporarily retain the primary structures (e.g., electrodes802) in place during fabrication of theemitter assembly114. Thesesupport structures806 may be subsequently removed, e.g., after electrodes802 are suspended in place via potting material412 (FIG.4).Support structures806 may definewidths810E of about 0.0020 inches.

FIG.8B is a 2-D representation of a hypotube-array design812 that includesmultiple instances800A-800D of thesecond hypotube design800 ofFIG.8A. As referenced above, in some examples, two or more emitter units114 (FIG.1) of an emitter array112 may be cut from a single continuous hypotube, or alternatively, cut from a common planar surface and then formed into a cylindrical hypotube. This technique removes the need to weldindividual emitters114 to wires, thus facilitating the manufacturing process. That is, in place of conductively coupled wires406 (FIG.4),individual hypotubes800A-800D may be conductively coupled via conductive-coupling supports814 that are cut from the same substrate as the emitters. Theexample design812 shown inFIG.8B also includes a plurality ofremovable supports816.Removable supports816 may initially be cut into the common substrate withhypotubes800A-800D and coupling supports814 to help retain these components in place during fabrication, and then subsequently removed after hypotubearray812 is assembled into functioning emitter units.

FIG.9 is a 2-D representation of athird example design900 for a laser-cut hypotube410 of an electronic emitter assembly400 (FIG.4). Similar to hypotube design800 (FIG.8), hypotube design900 (while in the planar configuration shown inFIG.9) may define a rectangle having acircumferential length910A of about 0.1 inch. Therectangular width910B (e.g., the longitudinal length ofhypotube900 along longitudinal axis116) can range from about 0.080 inches to about 0.090 inches.

As compared to hypotube designs700 (FIGS.7A and7B) and800 (FIGS.8A and8B), both of which define generally linear spark-gap configurations,electrodes902A-902D ofhypotube design900 are shaped and oriented so as to define substantially rounded orcircular spark gaps904A-904D. For instance,hypotube design900 may include two substantially ring-like electrodes902A,902C, each defining an outer radius of about 0.0210 inches and an inner radius of about 0.013 inches. In the center ofring electrodes902A,902C aredisc electrodes902B,902D, respectively.Disc electrodes902B,902D may define outer radii of about 0.0090 inches. Accordingly, electrode pairs902A/902B and902C/902D may define respective ring-shaped, or semi-ring-shaped spark gaps904 therebetween, having a gap width of about 0.0040 inches. Similar to hypotube800 (FIG.8),hypotube900 may initially include one or morevertical support structures906, which may be removed once electrodes902 are adhered in place.Support structures906 may definewidths910C of about 0.0030 inches, for example.

FIG.10 is aflowchart1000 illustrating an example technique for forming an electronic emitter assembly for an IVL catheter, for instance, theemitter assembly400 shown inFIG.4A. The technique ofFIG.10 includes cutting a hypotube according to an electrode design, e.g., one of designs700-900 ofFIGS.7A-9, respectively, so as to define one or more pairs of conductive electrodes aligned so as to define a respective spark gap therebetween (1002). The technique further includes inserting an elongated structure, such as innerelongated structure318 ofFIG.4A, into the lumen of the cut hypotube (1004).

In some examples, but not all examples, additional layers may be inserted betweenhypotube410 and the innerelongated structure318 to help provide structural support, improve thermal conductance or increase energy efficiency, as illustrated inFIG.4B. For instance, a pressure-reflective material, athermoplastic elastomer416, wire coils418, or apolyimide layer420 may be inserted, if not already present (1006). The technique ofFIG.10 further includes flowing apotting material412 around the assembled components and causing or allowing the potting-material layer412 to solidify so as to retain the assembled components in place relative to one another (1108).

In some examples, but not all examples, the technique ofFIG.10 includes removing a portion of thepotting material412 from between the conductive electrodes of the hypotube, so as to re-establish the spark gap(s) (1010). For instance,step1010 may include milling out the potting material between electrodes or removing the potting material via laser ablation, variable-speed-rotary-tool removal, or other machine removal. In other examples, prior to flowing the potting layer (1008), the technique ofFIG.10 may further include filling the spark gap(s) with an easily removable material to block the potting material, and then subsequently removing the material. In other examples, the hypotube may be over-molded onto an existing potting layer, such that the spark gap is not filled-in in the first place.

In some examples, the technique ofFIG.10 further includes removing obsolete structural components fromhypotube410. For instance, as shown inFIG.8A,temporary support structures806 may be removed from between electrodes802 once the electrodes802 are secured in place.

FIGS.11A and11B illustrate anexample flex circuit1100 for an electronic emitter assembly400 (FIG.4) of an IVL catheter104 (FIG.1). For instance, conductive electrodes (e.g., copper strips)1102A-1102C may be printed onto a flexible, planar substrate1106 so as to define respective spark gaps1104 therebetween. The flexible substrate1106 may then be rolled into the tubular shape shown inFIG.11B, and then wired to the rest of emitter assembly400 (FIG.4). Such techniques may significantly reduce the manufacturing time of anIVL catheter104 includingsuch circuits1100.

For purposes of illustration,FIG.11 includes some non-limiting example dimensions offlex circuit1100. For instance,flex circuit1100 may include acircumferential length1110A of about 0.082 inches, and anaxial length1110B (e.g., parallel to longitudinal axis116) of about 0.080 inches. The planar substrate may further define a primaryrectangular body1108 and twoaxial prongs1112A,1112B. Primaryrectangular body1108 may have dimensions of acircumferential length1110A of about 0.082 inches by anaxial length1110C of about 0.060 inches. Axial prongs1112 may similarly be substantially rectangular, definingcircumferential widths1110D of about 0.012 inches byaxial lengths1110E of about 0.020 inches.Axial prongs1112A,1112B may be circumferentially separated by agap1110F of about 0.046 inches.

FIGS.12A and12B illustrate twoexample wiring configurations1200A,1200B, respectively, for an emitter array112 (FIG.1) of anIVL device108 including two flex circuits1100A,1100B (e.g.,flex circuit1100 ofFIGS.11A and11B). In particular,FIG.12A shows anexample wiring configuration1200A in which theflex circuits1102A,1102B are wired in parallel. The top conductive wire1202 (solid line) leads to a voltage input, and the bottom conductive wire1204 (dashed line) leads to ground voltage.

FIG.12B shows anotherexample wiring configuration1200B in which theflex circuits1102A,1102B are wired so as to be independently actuatable. For instance, the topconductive wire1206 provides a connection between a voltage input andflex circuit1102B, and the middle conductive wire1208 (solid lines) provides a connection between the voltage input andflex circuit1102A. The bottomconductive wire1210 provides a common connection to ground voltage for both of flex circuits1102.

FIGS.13A and13B illustrate twoexample wiring configurations1300A,1300B, respectively for conductively wiring an electronic emitter array400 (FIG.4). In the example1300A shown inFIG.13A, elongated body includes an inner elongated structure1302 (e.g., polyimideinner layer420 ofFIG.4), and an outerelongated structure1304 having two nested layers: aninner layer1306 and anouter layer1308. A plurality ofconductive wires406, such as “flat” or “rectangular” wires, coil axially along an exterior surface of theinner layer1306 of outerelongated structure1304. Theouter layer1308 of outerelongated structure1304, such as a heat-shrink tube, thermoplastic tube, or potting material412 (FIG.4) may then be reflowed overtop of theconductive wires406, such that theconductive wires406 are embedded in theouter layer1308 of outerelongated structure1304.

In some examples,outer layer1308 of outerelongated structure1304 may terminate apredetermined distance1310 proximally from thedistal end1312 ofinner layer1306, such that distal portion ofconductive wires406 are exposed and may be adjusted underneath the interventional balloon110 (FIG.1).Conductive wires406 may include flat wires, round wires, or a combination thereof. For instance, in some examples,conductive wires406 include round wires with “flattened” portions near theemitters114.

Inwiring configuration1300A, the adhesiveouter layer1308 is “tacked” to theinner layer1306 to reinforce the structure of interventional balloon110 (FIG.1). This may help prevent theballoon110 from “accordioning” during insertion or removal of theIVL device108. The wires may also serve as a reinforcing member for the outerelongated structure1304.

By comparison,FIG.13B shows adifferent configuration1300B, in which theconductive wires406 are coiled directly around the innerelongated structure1302. In some examples, the use of flat wires (e.g., round wires with flattened portions near the emitters) helps reduce the overall radial profile of theIVL device108. In thisconfiguration1300B,conductive wires406 could also serve as a reinforcing member for the inner elongated structure1302 (e.g.,coil layer418 ofFIG.4B).

FIGS.14A-14D are conceptual cross-sectional drawings illustrating fourexample wiring configurations1400A-1400D, respectively, for an electronic emitter array112 ofcatheter104 ofFIG.1. In each of these four examples,conductive wires406 run distally along an outer surface of innerelongated structure318 but are not rigidly coupled to innerelongated structure318.

In the firstexample wiring configuration1400A ofFIG.14A, conductive wire(s)406 extend generally linearly along the distal direction, e.g., along to centrallongitudinal axis116. In this configuration, theemitters1406 may be wired in series, or in other examples, a combination of parallel and serial wiring.

By comparison, in the secondexample wiring configuration1400B ofFIG.14B, conductive wire(s)406 coil helically around innerelongated structure318 according to a “single wrap” configuration. In the single-wrap wiring configuration1400B, two ormore wires406A,406B are inter-coiled, with respective longitudinal spaces between adjacent coil turns. In these “coiled” configurations shown inFIGS.14B,14C, and14D, the wire coils help provide structural support for innerelongated structure318, e.g., by formingcoil layer418 ofFIG.4B. In some such examples, the emitter array may be wired according to an “n+1” configuration, in which the number ofconductive wires406 is one more than the number ofemitters1406, such that each emitter has a unique voltage-supply wire, but all share a common ground wire.

In the thirdexample wiring configuration1400C ofFIG.14C, conductive wire(s)406 coil helically around innerelongated structure318 according to a “double wrap” configuration. In the double-wrap wiring configuration1400C,wires406 are inter-coiled as wire pairs, with longitudinal spaces between adjacent pairs of coil turns. Wire-jacket portions1408 may be removed (e.g., ablated) as necessary forconductively coupling wires406 to electrode hypotube410 (FIG.4).

In the fourthexample wiring configuration1400D ofFIG.14D,conductive wires406 coil helically around innerelongated structure318 according to a “quadruple wrap” configuration. In the quadruple-wrap wiring configuration1400D,wires406 are inter-coiled as groups of four wires, with longitudinal spaces between adjacent groups of four coil turns. Wire-jacket portions1408 may be removed (e.g., ablated) as necessary forconductively coupling wires406 to electrode hypotube410 (FIG.4). In other examples, wires may be grouped and coiled in numbers greater than four.

FIG.15A is a conceptual diagram illustrating anexample wiring configuration1500A for anelectronic emitter array1502A having fouremitter units1504A-1504D, andFIG.15B is a conceptual diagram illustrating anexample wiring configuration1500B for anelectronic emitter array1502B having fiveemitters1504A-1504E. While only four-emitter and five-emitter assemblies1502 are shown, it is to be understood that any suitable and practical number of emitter units1504 may be implemented withinIVL device108. As referenced above, bothwiring configurations1500A,1500B are examples of an “n+1” configurations, in which the number of conductive wires is one more than the number of emitters1504, such that each emitter1504 has a unique voltage-supply wire, but all emitters1504 share acommon ground wire1506. In such configurations, individual emitters1504 are independently actuatable providing enhanced control over the IVL therapy for the clinician.

FIG.16A is a conceptual diagram illustrating a first example wiring configuration1600A for anelectronic emitter array1602 having fouremitter units1604A-1604D.FIG.16A, likeFIGS.15A and15B, shows the emitter units1604 wired according to the “n+1” configuration, and a configuration in which emitter assemblies1604 wired in parallel. Some example benefits of a parallel wiring configuration1600A include the ability to transmit a higher electrical current across the emitter units1604. A parallel wiring configuration1600A also enables each individual emitter unit1604 to be actuated (or “fired”) independently of the other emitter units. Additionally, with a parallel wiring configuration1600A, the total resistance of the IVL system100 (FIG.1) may be reduced. For instance, by individually powering a single emitter unit1604, a greater electrical current may be generated across the spark gap404 (FIG.4), thereby reducing the necessary number of resistors in the corresponding electrical circuit.

Configuration1600A may also allow for a reduction in the overall voltage through the system, e.g., translating to a reduction in energy consumption. The ability to individually power each emitter1604, and the ability to choose a sequence of order of firing of each emitter unit1604, allows for greater overall control of theIVL device108, including how and where the applied energy is directed, as detailed further below.

FIG.16B is a conceptual diagram illustrating a second example wiring configuration1600B for theelectronic emitter array1602 ofFIG.16A. In wiring configuration1600B, a combination of both parallel and serial wiring techniques may be implemented, enabling advantages of both configurations. For instance,emitters1604A and1604B are connected in series, whereas other emitters1604 are connected in parallel. In particular, wiring configuration1600B enables the clinician to simultaneously actuate: (1)emitters1604A-1604D (e.g., usingwires1606A and1606C); (2)emitters1604C and1604D (e.g., usingwires1606B and1606C); or (3)emitters1604A and1604B (e.g., usingwires1606A and1606B). However,FIG.16B is not intended to be limiting—any suitable wiring combination for emitters1604 is contemplated and encompassed herein.

FIG.17A is a conceptual diagram, andFIG.17B is a cross-sectional view, illustrating anIVL device1700 having an array (e.g., emitter array112 ofFIG.1) of optical-based pressure-wave emitters1702A-1702C. As used herein, optical-based emitters1702 can include the distal ends or distal portions of respective optical fibers ortubes1704A-1704C, whichIVL device108 ofFIG.1 may include in addition to, or alternatively to, one or more electronic emitter units, as described above.

According to some non-limiting examples, optical fibers1704 may deliver, e.g., about 20-100 millijoules of energy within about one millisecond into theinflation fluid408, such as water, a saline/contrast-fluid mixture, another fluid, or a combination thereof, withininterventional balloon110 in order to generate and propagate high-energy pressure waves. However, these values are merely illustrative, and the amounts of energy and/or time may be adjusted for a particular clinical application. In some examples, an emitted optical pulse width (e.g., emitted-light duration) may be 5 nanoseconds or more.

Based on varying clinical needs,IVL device1700 may include any suitable number of optical fibers1704. In some examples,IVL device1700 is configured to transmit a laser signal having a wavelength from about 1064 nanometers (nm) to about 1460 nm, though shorter wavelengths may be similarly effective. Example diameters for optical fibers1704 can range from about 50 microns or less to about 200 microns or greater, depending on the particular clinical application.

As shown inFIG.17A, in some examples, thedistal emitter portion1702A ofoptical fiber1704A may be oriented at a predetermined angle “θ” relative to centrallongitudinal axis116. For instance, to protect innerelongated structure318,distal emitter portion1702A may be oriented at an angle θ of greater than 90 degrees, such as greater than about 114 degrees. Foroptical fiber1704A, only a distal-most surface or distal-most end ofemitter portion1702A is angled away from innerelongated structure318. In other examples, such as the example ofoptical fiber1704B, an entiredistal portion1702B may be bent or angled away from innerelongated structure318.

Optical emitters1702 of optical fibers1704 may be positioned either circumferentially around inner elongated structure318 (e.g., as shown inFIG.17B), or in other examples, longitudinally along innerelongated structure318, or in still other examples, a combination thereof to emit and deliver high-energy pressure waves. For instance, optical fibers1704 may be adjacent to inner elongated structure318 (e.g.,1704A) for circumferential lesion treatments, or radially off-centered (e.g.,1704B) for non-circumferential lesion treatments. Some example benefits of using more than one optical fiber1704 include reducing the overall cross-sectional profile ofIVL device1700 by positioning optical fibers1704 around the proximal portion of the catheter elongated body106 (FIG.1). Additionally, a greater number of optical fibers1704 allows for a more controlled pressure wave. In addition to directing the energy based on where the optical fibers1704 are placed about theIVL catheter104, the size of the cavitation bubble may be controlled based on a selected diameter (e.g., cross-sectional area) of optical fibers1704. These optical fibers1704 may be individually or simultaneously actuated based on the needs of the treatment, e.g., allowing for asingle IVL device108 that can treat both circumferential calcified lesions as well as nodular calcified lesions.

FIG.18 is a cross-sectional diagram of an example IVL device1800 (e.g.,IVL device108 ofFIG.1) with an interventional balloon1810 (e.g.,balloon110 ofFIG.1) having a multiple-layered construction for enhanced durability. As shown,balloon1810 may have anouter layer1802 and aninner layer1804, for the purposes of reinforcement. Either or both of reinforcinglayers1802,1804 may include a separate extrusion that goes over the top of theballoon1810, with another layer over the top of this pressure-holding layer.

The example shown inFIG.18 represents just one of multiple solutions to the potential risk of balloon rupture. For instance,balloon1810 may be formed from a single multi-layered extrusion, wherein a thin, more-compliant layer1802 on the outside of the balloon is softer and less prone to tearing than an inner, high-pressure, non-compliant (or “less compliant”)holding layer1804. For instance, one example structure could comprise a high-pressureinner holding layer1804 that makes up, e.g., between 70% and 100% of the thickness of the balloon wall, such as Nylon-12, or Pebax-72D. Theoutside layer1802 is made from a more-compliant substance such as urethane, Pebax, or any other suitable material with a medium-to-low durometer measurement, e.g., of about 63D or lower.

Another solution is to form the balloon from twoseparate extrusions1802,1804, e.g., aseparate extrusion layer1802 on the outside of the balloon placed upon the exterior surface of an inner non-compliant orsemi-compliant balloon1804. Another solution is to form theballoon1810 from a thin polymerinner layer1804 covered by reinforcinglayers1806 such as polymer fibers, like Aramid or UHMWPE, with atop coating1802 for fiber encapsulation. Theouter layer1802 may be a plurality of reinforcing layers, for instance, a set of sixteen braided fibers, and four to eight (inclusive) longitudinal fibers, as one non-limiting example. Other variations of braid patterns are similarly viable, such as those including thirty-two fibers or forty-eight fibers. Additionally, the reinforcing fibers may be arranged in an orthogonal textile pattern, such as a mesh sheet cut into pieces, as opposed to (or in addition to) being braided directly onto theballoon1810.

While not shown inFIG.18, another solution against potential balloon rupture is to coat the balloon with an abrasion-resistant coating, such asexterior coating326 ofFIG.3. This solution may be accomplished by applying the coating to theballoon1800 through a dip, a spray, or a roll-cast. According to some examples, this coating may be or may include a polymer, such as urethane, parylene, silicone, or a thermoplastic polyurethane (TPU). These coatings may allow for aballoon1810 that holds a high pressure while protecting the balloon structure from damage due to contact with the calcified lesions within the target vessel. Although not illustrated, another technique includes implementing a compliant balloon body to allow conformance to plaque and puncture resistance. In the example of this solution, non-compliant cones on either end of the balloon would be implemented to prevent the pressure wave from propagating proximal to, or distal from, theballoon110.

FIGS.19 and20 illustrate twoexample IVL devices1900,2000, respectively, havinginterventional balloons110 withprotective structures1902,2002, or “protective cages.” Specifically,FIG.19 is a profile view of a firstexample IVL device1900 having a first-suchprotective structure1902, andFIG.20 is a side view of a secondexample IVL device2000 having a second-suchprotective structure2002.

Theseprotective structures1902,2002 are configured to provide similar rupture-protection to the more-continuous balloon outer layer orcoating1802 described above with respect toFIG.18. According to either of these examples,balloon110 can have a cage-like structure overtop of it, thereby reducing direct physical contact (e.g., friction) between the exterior surface of the balloon and the calcified-plaque lesion appended to the vessel wall.

The cage-like structures1902,2002 may be or may include a metal, such as SST or nitinol, or a polymer. In a multi-nested-layer balloon (e.g.,balloon1800 ofFIG.18), theprotective structure1902,2002 could be disposed between the outer andinner balloon layers1802,1804. In some examples, the cage-like structure1902,2002 includes multiple longitudinal members, e.g., extending parallel to centrallongitudinal axis116. In some such examples,protective structure1902,2002 may be selected to include an odd number of longitudinal members, such as three longitudinal members or five longitudinal members, in order to promote re-wrap of the respective balloon prior to withdrawal ofIVL device108 from the patient's vasculature. These longitudinal members or bars may be interconnected as a stent-like structure, such that the structure has a predetermined size and shape that does not vary (or varies by a relatively small amount) during inflation ofballoon110.

According to some examples, theprotective structure1902,2002 is rigidly coupled to the exterior surface of theballoon110. In some such examples, theprotective structure1902,2002 is rigidly coupled to the proximal and distal end portions ofballoon100, but not to a longitudinally central balloon portion.

The example ofFIG.19 shows a less-comprehensiveprotective structure1902, as compared to the exampleprotective structure2002 ofFIG.20. For instance,protective structure1902 includes, as non-limiting examples, two (top and bottom)longitudinal elements1904, and about thirteencircumferential elements1906. By comparison,protective structure2002 is shown to include a more-continuous wire-mesh configuration or window-screen configuration having dozens or hundreds of interwoven longitudinal and circumferential elements.

FIG.21 illustrates an example IVL device2100 (e.g.,IVL device108 ofFIG.1) including a pair of scoringmembers2102A,2102B. Scoring members2102 are configured to physically contact and abrade (e.g., through friction applied across a substantially small surface area, corresponding to a substantially high stress-pressure at that point) an interior surface of a calcified-plaque lesion to help fragment and disintegrate the lesion.

In some examples, scoring members2102 may be coupled to a protective structure (e.g.,protective cages1902,2002 ofFIGS.19 and20, respectively) within or over theballoon110. In some examples,balloon110 may include a single scoring member2102. In other examples, multiple scoring members2102 may be distributed, rotationally symmetrically or asymmetrically, about the circumference ofballoon110. During the IVL procedure,balloon110 may be circumferentially rotated to apply a particular scoring member or members2102 against the calcified lesion. In some examples, scoring members2102 may be formed from a metal, such as an SST or a nickel-titanium alloy (e.g., Nitinol), a metal wire, a printed metal ink (which may contain a very small amount of polymer binder from processing), tungsten, or a polymer.

In some examples, such as the example shown inFIG.21, scoring members2102 may include generally flat or planar external surfaces. In other examples, scoring members2102 may include toothed or serrated external surfaces, e.g., to increase kinetic friction when contacting the calcified-plaque lesion.

FIG.22 illustrates an example IVL device2200 (e.g.,IVL device108 ofFIG.1) including afracturing element2202 configured to help fragment the calcified-plaque lesion during the IVL procedure. As shown inFIG.22, fracturingelement2202 includes an elongatedconductive wire2204, and a plurality ofpiezoelectric elements2206 distributed longitudinally along thewire2204.

Fracturing element2202 provides at least two advantages. First, whenconductive wire2204 is aligned against the calcified-plaque lesion, the narrow-cross sectional area ofconductive wire2204 substantially increases a pressure applied to the lesion along the axis of the wire, enabling the clinician to control the particular location at which the lesion begins to fragment. Second, when an alternating current (AC) is applied throughconductive wire2204,piezoelectric elements2206 are configured to rapidly expand and contract, thereby generating additional pressure waves that are focused directly against the exterior surface of the lesion.

In some examples, fracturingelement2200 includes a distal protective element, such as an embolic protection element, as described further below with respect toFIG.24A. For instance, the distal protective element may be coupled to a distal portion ofconductive wire2204. Additionally, or alternatively towire2204, fracturingelement2200 can include a braided layer, such as a Nitinol braid.Piezoelectric elements2206 may be rigidly coupled to an exterior surface of the braid, and the braid may be coupled to the exterior surface ofballoon110. This braid may perform similar functions as those described above with respect towire2204.

FIG.23 illustrates an IVL device2300 (e.g.,IVL device108 ofFIG.1) with anexample spring mechanism2302. With some previous devices, theinterventional balloon110 can become difficult to insert into and remove from an introducer sheath (not shown) during an IVL procedure. This may be caused, for example, by excessively bulky proximal and/or distal balloon cones (as compared to, e.g.,distal balloon cone1404 ofFIG.14A), or a lack of effective folding or wrapping ofballoon110 during and/or after deflation. In some examples, this problem may be addressed by reducing the balloon's radial profile (e.g., cross-sectional area) while it is in an uninflated or deflated state. This could be accomplished by longitudinally stretching theballoon110 while bonding the proximal and distal ends of the balloon to innerelongated structure318.

Another technique for reducing the profile ofballoon110, which is illustrated inFIG.23, is to incorporate aspring2302 within innerelongated structure318. Thespring2302 should be longitudinally compressed when bonded (e.g., atproximal end2304A and distal end2304B) to innerelongated structure318.Balloon110 may then be bonded to innerelongated structure318 such that, whenspring2302 is allowed to expand back to its rest length, innerelongated structure318 andballoon110 similarly expand along the longitudinal direction and compress radially inward.Balloon110 may also be stretched longitudinally about the tube318 (as described above) during the bonding process to further facilitate this technique. During inflation,balloon110 will still expand to its pre-formed shape, while the innerelongated structure318 will slightly compress along the longitudinal direction. That is, the proximal and distal points at whichballoon110 is bonded to innerelongated structure318 may slightly compress toward one another asballoon110 expands radially outward.

Another technique for reducing the cross-sectional profile ofballoon110 is to improve balloon re-wrap after deflation during a procedure. This can be accomplished in a number of ways, such as by incorporating or embedding a plurality of longitudinal wires into the balloon body. These longitudinal wires may help define pleats or pre-determined folding locations forballoon110, rather than allowing the balloon material to “bunch up” in a disordered fashion. While any number of longitudinal wires may be incorporated, an odd number of longitudinal wires can help prevent the balloon from collapsing into a symmetrical plane, such as a “paddle” or “pancake” configuration of the balloon. Additionally, the longitudinal members may be radiopaque so that they can be used to visualize theinflated balloon110 and its apposition relative to the vessel wall during the IVL procedure. Such configurations can obviate the use of a separate fluid contrast medium, thereby potentially reducing an overall duration of the IVL procedure. In some examples, these longitudinal wires could consist of metal wires (e.g., flat, round, or irregular-shaped, such as pentagonal), a printed ink (e.g., a metal or polymer ink), or a polymer structure.

FIG.24 illustrates an example IVL device2400 (e.g.,IVL device108 ofFIG.1) including a distalprotective member2402. According to some examples, a distalprotective member2402 may be positioned at a distal end portion ofIVL device2400. In some examples (but not all examples), the distalprotective member2402 includes an elongated element2404 (e.g., a guidewire) that extends, e.g., throughguidewire lumen322 of innerelongated structure318, and a distalexpandable member2406. In some such examples,expandable member2406 is configured to extend distally outward fromdistal port324 and expand radially outward into the expanded configuration shown inFIG.24. Theinner lumen322 of innerelongated structure318 surrounding the extended distalprotective member2402 may be compatible for guidewires from 0.010″ to 0.035″. Therefore, the guidewire lumen size can range from 0.011″ up to 0.038″ to allow for free guidewire movement.

The distalprotective member2402 is configured to capture calcified particulates that are generated during the IVL procedure.Expandable member2406 may include a basket-frame design, as shown inFIG.24A, but other suitable designs are contemplated as well. In some such examples, thebasket frame2406 may be or may include a Nitinol cut-tube (similar to a stent) or a Nitinol wireframe. The material that makes up thebasket2406 may be a thin polymer with ablated holes or a fiber mesh. According to some examples, thebasket frame2406 could be placed outside theballoon catheter104 and is designed so that the distal protective member'sshaft2404 is compatible with the balloon dilation (wherein theballoon110 presses up against theshaft2404 of the filter device2402).

Theseprotective members2402 could also be rapidly exchanged on theballoon catheter104. A rapid exchange port may be proximal of theballoon110 or distal of theballoon110. The distalprotective member2402 may enter or exit the balloon catheter at the hub, proximal of the balloon, or distal of theballoon110. This distalprotective member2402 may also be modular (e.g., removable) in nature, so that it is only present on thedevice2400 when needed for a procedure.

FIG.25 illustrates an example ofIVL system100 ofFIG.1, including a closed-loop energy-delivery feedback mechanism. In some current IVL systems, the amount of delivered energy is fixed and not tailored to the clinical need. This disclosure allows for the automatic delivery of energy based on the clinical scenario presented, in order to improve treatment efficacy and efficiency, via a sensor2502 that measures, e.g., fluid pressure, fluid amount/rate, and/or temperature. Any combination or sole use of the monitoring provided by the controls as disclosed herein may provide input to determine a maximum pressure-wave intensity and/or heat level to be generated by the emitters.

According to some examples,system100 may include one or more sensors2502, e.g., incorporated withinenergy generator102,catheter104, or both. Based on data received from sensor2502, system100 (e.g., processing circuitry ofgenerator102, or a separate computing device associated with system100) is configured to dynamically (e.g., in real-time) adjust energy levels output bygenerator102.

For instance, sensor(s)2502 may include as non-limiting examples: an inflation-fluid flow-rate monitor, an inflation-fluid pressure monitor, a vessel-wall surface monitor, a vessel-diameter monitor, a balloon-diameter monitor, a plaque-fragmentation monitor, or any other type of sensor configured to provide insight regarding a current progress of the IVL procedure. In some examples, sensor2502 is configured to detect the resonant frequency (e.g., natural frequency or harmonic frequency) of the calcium in the lesion.

Based on real-time monitoring of the sensor data from sensor(s)2502,system100 may be configured to dynamically adjust one or more of: an electric-current level, a voltage level, an electric pulse duration or frequency, a light intensity, a light-pulse duration, a light-pulse frequency, or any other suitable parameter affecting an amount or rate of energy delivered via emitter array112. For the specific example of plaque-lesion resonant frequency,system100 may be configured to automatically adjust the emitter sonic frequency to match the detected resonant frequency of the lesion to more-effectively fragment the lesion.

In some examples additionally or alternatively to dynamically adjusting energy levels,system100 is configured to automatically terminate an applied voltage in response to certain conditions being met, including (but not limited to) a threshold fragmentation of the calcified-plaque lesion being achieved or a detected system parameter being outside threshold levels (e.g., a suspected malfunction ofballoon110 or another component).

As one illustrative example,IVL system100 may be configured to monitor a fluid pressure ofballoon110. For instance, sensor2502 can include a pressure transducer configured to interact with theinflation lumen320. Accordingly,system100 can further include a three-way fluid connector (e.g.,catheter hub306 ofFIG.3) configured to fluidically couple an inflation syringe (e.g., inflation port310),inflation lumen320, and a pressure line running back toenergy generator102. The pressure transducer may be integrated intoenergy generator102 and fluidically coupled along the pressure line. In some such examples, the fluid line may also include a transducer protector, such as a valve or membrane, configured to prevent theinflation fluid408, e.g., a saline/contrast-fluid mixture, from entering components ofenergy generator102.

As another illustrative example, IVL system100 (e.g., processing circuitry ofenergy generator102 or of another computing device associated with system100) may be configured to monitor an electrical impedance of one or more components ofsystem100. When plasma is created within the spark gap404 between the electrode pair402 (FIG.4), the local electrical impedance will drop, thus causing system100 (upon detection) to terminate the applied voltage. Additionally, or alternatively, system100 (e.g.,measurement unit216 ofFIG.2) may be configured to monitor an electrical-current level produced bygenerator102 as it is output and automatically terminate the applied voltage in response to an above-threshold change in the monitored current.

In other examples, rather than dynamically modifying energy levels (e.g., applied voltage levels, or the like),system100 may be configured to apply the energy level (e.g., voltage level) as an “all or nothing” (e.g., binary 0 or 1). For instance,system100 may only transmit energy, at a predetermined level, throughcatheter104 while certain conditions are determined to be met, as indicated by data from sensor2502. Additionally, or alternatively,system100 may be configured to adjust other parameters. For instance,system100 may be configured to dynamically adjust a longitudinal length and/or an inflation diameter ofballoon110, as needed.

FIG.26 illustrates anexample handle2600 that may be coupled at the proximal portion302 (FIG.3) ofIVL catheter104 ofFIG.1.Catheter104 may includehandle2600 in addition to, or instead of, catheter hub306 (FIG.1). In instances in which bothhub306 and handle2600 are present, handle2600 may couple to a portion ofelongated body106 extending proximally throughhub access port308.

Existing IVL catheters require a costly generator to power the catheter. In the example shown inFIG.26,catheter handle2600 includes an integratedpower supply2602.Power supply2602 may include a battery, capacitor, or any other suitable integrated power source configured to deliver sufficient power levels to actuate emitter array112 (FIG.1). That is, in some examples, system100 (FIG.1) may includehandle2600 in place ofenergy generator102. In other examples, handle2600 may be configured to supply supplemental or auxiliary power to emitter array112. In some examples,catheter104 may be configured to removably couple toenergy generator102 and function while either connected or disconnected, similar to a laptop or other mobile device.

Typical IVL systems and devices are configured to emit high-energy pressure waves that propagate across all spatial dimensions. This attribute may be relatively effective for ring-like calcified-plaque lesions, e.g., that appear around the entire inner circumference of the vessel wall. However, other lesion configurations are not as effectively treated, or alternatively may waste significant amounts of energy due to the inefficient application of the energy. Accordingly, a number of features and techniques are disclosed herein, enabling IVL device108 (FIG.1) to focus the emitted high-energy pressure waves in a particular spatial direction or limited range of directions.

For instance,FIG.27 is a cross-sectional view of an IVL device2700 (e.g.,IVL device108 ofFIG.1) having a firstexample wave director2702. In some examples,wave director2702 includes a layer of material oriented along just a portion of the inner circumference ofballoon110 and extending longitudinally (e.g., proximally and distally) throughballoon110. The material is configured to substantially absorb and/or reflect pressure waves that contact the material, thereby reducing energy that is wasted by being channeled in arbitrary directions. As described above, this acoustically opaque material can include, e.g., a ceramic, porcelain, diamond, polyimide, polyether ether ketone (PEEK), a similar material, or any suitable combination thereof.

In the example shown inFIG.27,wave director2702 is shown to have a half-moon-shape cross-sectional profile, although other configurations are contemplated. For instance,wave director2702 may define a substantially semi-circular cross-sectional profile, or alternatively, include a relatively thin reflective layer coated onto the portion of the inner surface ofballoon110.

In some examples,wave director2702 includes a distinct lumen “pocket” that can be inflated or deflated as needed with typical balloon angioplasty. In some examples, a fluid lumen separate from inflation lumen320 (FIG.3) is configured to deliver a gas to inflate the pocket so as not to interfere with inflation of theballoon110 itself. During use ofIVL device2700, the pressure waves will be unable to penetrate the gas pocket and will therefore be absorbed and or reflected toward the opposite circumferential direction.

Additionally, or alternatively to an absorbent and/or reflective material,wave director2702 ofFIG.27 may be or may include at least one of the pair of electrodes402 (FIG.4) of anelectronic emitter unit400. For instance, the half-moon-shapeddirector2702 may include one or both of theelectrodes402 to directionally focus the emitted pressure waves to fragment a target calcification.

Additionally, or alternatively to the reflective material, in some examples, the compositional material ofballoon110 may be strategically varied to provide for directionally targeted wave emission. For instance, the material ofballoon110 may be configured to be thicker along some portions of the circumference than along other portions. In some examples, theballoon110 may incorporate a more-transmissive material along a first portion of its circumference and a more-absorbent and/or more-reflective material along a second portion of its circumference.

In some examples, a fluoroscopic wire (e.g.,conductive wire2204, as described above with respect toFIG.22) or othervisual indicator2704 may be positioned oppositewave director2702. Thevisual indicator2704 helps the clinician orient (e.g., rotate)IVL device2700 toward the target calcification prior to beginning targeted fragmentation. Also, as described above with respect toFIG.22, in some examples,piezo elements2206 can be mounted or expanded to an off-center location (e.g., asymmetrically distributed) onto or withinballoon110, providing an increase in energy to that side. In such examples, the tissue region adjacent thepiezo elements2206 would receive a greater amount of energy, thus enabling directionally targeted lesion fragmentation.

FIG.28A is a perspective view, andFIG.28B is a cross-sectional view of a second example directionally focused IVL device2800 (e.g.,IVL device108 ofFIG.1).IVL device2800 includes an array of emitter assemblies2814, wherein each emitter assembly2814 includes two or more individual emitter units2816 distributed circumferentially around innerelongated structure318. Each individual emitter unit2816 can include an electrode pair, a piezo element, or an optical emitter.

As shown inFIGS.28A and28B, emitter units2816 may be configured to mount or expand to an off-center location within the cross-sectional area ofballoon110, thereby providing an increase in energy delivered to the respective side ofballoon110. In some examples, each individual emitter unit2816 is configured to be independently actuatable. In other examples, all individual emitter units2816 of different emitter assemblies2814 that are aligned along a common longitudinal axis are configured to be commonly actuatable. Additionally, or alternatively, individual emitter units2816, as mounted onstalks2818, can be configured to tilt or angle toward and away from innerelongated structure318, to further control directional energy transmission.

Also, as shown inFIGS.28A and28B,IVL device2800 can include one or more radiopaquevisual indicators2704 to help with device orientation relative to the target treatment site. However, as shown inFIG.28B,visual indicators2704 should be asymmetrically distributed about the circumference ofballoon110 to prevent ambiguous balloon-orientation determinations.

FIG.29A is a perspective view, andFIG.29B is a cross-sectional view of a third example directionally focused IVL device2900 (e.g.,IVL device108 ofFIG.1).IVL device2900 is an example ofIVL device2800 ofFIG.28, except for the differences noted herein. In particular,interventional balloon110 ofIVL device2900 includes two or more elongated sub-balloons2902 distributed circumferentially around innerelongated structure318. Each sub-balloon2902 is configured to retain a subset of emitter units2816 that are oriented along a common longitudinal axis. Each emitter-unit subset is configured to be independently actuatable from the other emitter-unit subsets, and the respective sub-balloon2902 is configured to help apply the emitted pressure waves to a particular portion of the circumference of the interior surface of the target vessel.

In some examples, each sub-balloon2902 is configured to be individually inflatable, e.g., according to a different inflation rate or amount than the other sub-balloons. In this way, IVL device may be positioned off-center toward a particular portion of the vessel wall (e.g., the calcified lesion). Such examples enable the respective subset of emitter units2816, including a corresponding scoring member2102 (FIG.21), if present, to be positioned even closer to the target treatment site.

As described above, the emitters2618 can tilt away from the innerelongated structure318 to be closer to the inner diameter wall of the balloon110 (e.g., instead of being adjacent to the inner elongated structure318). Accordingly, the energy delivered by these emitters2816 can be more focused on the wall of the vessel to which they are positioned closest. This, in combination with a cutting wire (e.g.,conductive wire2204 of fracturingelement2202 ofFIG.22), can create a high-stress focal point to more-efficiently and/or more-effectively break up a nodular calcified lesion.

Additionally, in the examples ofFIGS.28A and29B, energy generator102 (FIG.1) may independently and selectively control the emitters2816 that reside about the circumference ofIVL device2900. This means that, even without tilting or moving the emitters2816 in any way, the energy delivery may be controlled by only firing the emitters2816 closest to the calcified lesion. Additionally, if the treatment presented requires full-circumference energy delivery, all emitters2816 may still be fired, allowing for a more traditional style of treatment to occur.

It should be noted that these emitters2816 can all be located within thesame balloon110, as is shown inFIGS.28A and28B, or within their own, separate sub-balloons2902, as shown inFIGS.29A and29B. Additionally, while the relative alignments shown inFIGS.28B and29B allow for just one array of emitter units, it should be noted that these emitters2816 can be placed about the catheter throughout theballoon110, and the quantity of possible emitters is only dictated by the length of theballoon110 being used.

Claims (20)

What is claimed is:

1. A medical device, comprising:

an elongated body;

a balloon positioned at a distal portion of the elongated body, the balloon configured to receive a fluid to inflate such that an exterior surface of the balloon contacts an interior surface of a target treatment site within a vasculature of a patient; and

one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon, the one or more pressure-wave emitters configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site,

wherein at least one of the one or more pressure-wave emitters comprises an electronic emitter comprising a first electrode and a second electrode,

wherein the first electrode and the second electrode are arranged to define a spark gap between the first electrode and the second electrode,

wherein the first electrode extends radially inward through the elongated body and at least partially inward into an inner lumen of the elongated body, and

wherein the second electrode comprises a portion of a hypotube.

2. The medical device ofclaim 1,

wherein the spark gap comprises a first spark gap;

wherein the electronic emitter further comprises a third electrode; and

wherein the third electrode is arranged so as to define a second spark gap between the second electrode and the third electrode.

3. The medical device ofclaim 2, wherein the first electrode, the second electrode, and the third electrode are all portions of a common cylindrical surface of the hypotube.

4. The medical device ofclaim 3, wherein the first electrode and the third electrode both define rounded triangular shapes, and wherein the second electrode defines a parallelogram shape.

5. The medical device ofclaim 3, wherein the first electrode, the second electrode, and the third electrode all define rounded rectangular shapes.

6. The medical device ofclaim 3, wherein the first electrode and the third electrode both define oval shapes, and wherein the second electrode defines a semi-cylindrical shape.

7. The medical device ofclaim 1, wherein the electronic emitter further comprises a coupler layer positioned radially between the elongated body and the second electrode.

8. The medical device ofclaim 1,

wherein the first electrode is ring-shaped;

wherein the second electrode is disc-shaped; and

wherein the first electrode is positioned around the second electrode.

9. The medical device ofclaim 8,

wherein the electronic emitter further comprises a third electrode and a fourth electrode;

wherein the third electrode is ring-shaped and the fourth electrode is disc-shaped;

wherein the third electrode is positioned around the fourth electrode.

10. The medical device ofclaim 9, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are all portions of a common cylindrical surface of the hypotube.

11. The medical device ofclaim 1, wherein the hypotube defines a longitudinal length from about 0.080 inches to about 0.090 inches, and an outer circumference from about 0.10 inches to about 0.12 inches.

12. The medical device ofclaim 1, wherein the first electrode is rectangular-prism shaped.

13. The medical device ofclaim 1, further comprising an energy generator removably coupled to the elongated body and removably conductively coupled to the one or more pressure-wave emitters.

14. The medical device ofclaim 13, further comprising a sensor configured to generate sensor data indicative of at least one parameter.

15. The medical device ofclaim 14, wherein the energy generator is configured to change an amount of energy delivered based on the sensor data.

16. The medical device ofclaim 15, wherein the energy generator is configured to change a variable selected from the group consisting of a current level, a voltage level, a pulse duration, a pulse frequency, a light intensity, and combinations thereof to thereby change the amount of energy delivered.

17. The medical device ofclaim 14, wherein the sensor data is selected from the group consisting of fluid-pressure data, fluid rate data, temperature data, and combinations thereof.

18. The medical device ofclaim 14, wherein the sensor is selected from the group consisting of an electrical-impedance monitor, an inflation fluid-pressure monitor, a vessel-wall surface monitor, a vessel-diameter monitor, an interventional-balloon diameter monitor, a plaque-fragmentation monitor, and combinations thereof.

19. The medical device ofclaim 14, wherein the sensor comprises a resonant-frequency sensor, and wherein the energy generator is configured to change a pressure-wave frequency to approximate a resonant frequency of the calcified lesion.

20. The medical device ofclaim 14, wherein the energy generator is configured to terminate an applied voltage based on the sensor data.

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